An ALOHA system, or simply ALOHA, is a computer networking system providing a wireless packet data network. In a pure Aloha system, a user can transmit at any time but risks collisions with other users' messages. A modified version of the Aloha system, slotted Aloha, provides a reduced chance of collisions by dividing a communication channel into time slots and generally requiring that a user send only at the beginning of a time slot.
Slotted ALOHA performs better than Pure ALOHA as the probability of collision is less in slotted ALOHA as compared to Pure ALOHA because the base station waits for the next time slot to begin, which lets the frame in a previous time slot pass and avoid the collision between the frames. Slotted ALOHA is a refinement over the pure ALOHA. Slotted ALOHA requires that time be segmented into slots of a fixed length exactly equal to the packet transmission time. A packet arriving to be transmitted at any given base station is delayed until the beginning of the next slot.
As ALOHA presently exists, any strength can be competing with any other strength at the same instant, thus increasing the likelihood of collisions. In other words, ALOHA functions as a survival of the fittest protocol, where the weaker endpoints are adequately exceeded in strength by a competitor so that the stronger endpoint is demodulated and decoded. Demodulation generally requires an adequate carrier to interference ratio over competing radio frequency signals. If all the endpoints' uplink attempts were within each other's carrier to interference ratio requirements, none would succeed. Thus, improved methods of managing communication networks to reduce the likelihood of collisions are needed.